Generalized Quantum Measurement in Spin-Correlated Hyperon-Antihyperon Decays

The rapid developments of quantum information science(QIS)have opened up new avenues for exploring fundamental physics.Quantum nonlocality,a key aspect for distinguishing quantum information from classical one,has undergone extensive examinations in particles’decays through the violation of Bell-type inequalities.Despite these advancements,a comprehensive framework based on quantum information theory for particle interaction is still lacking.Trying to close this gap,we introduce a generalized quantum measurement description for decay processes of spin-1/2 hyperons.We validate this approach by aligning it with established theoretical calculations and apply it to the joint decay of ΛΛ pairs.We employ quantum simulation to observe the violation of Clauser–Horne–Shimony–Holt inequalities in η_(c)/χ_(c0)→ΛΛˉprocesses.Our generalized measurement description is adaptable and can be extended to a variety of high energy processes,including decays of vector mesons,J/ψ,ψ(2S)→ΛΛ,in the Beijing Spectrometer Ⅲ(BESⅢ)experiment at the Beijing Electron Positron Collider(BEPC).The methodology developed in this study can be applied to quantum correlation and information processing in fundamental interactions.

Masses of the conjectured H-dibaryon at different temperatures

We present a lattice QCD determination of masses of the conjectured H-dibaryon,denoted as mH,at nine different temperatures:T/T_(c)=0.24,0.63,0.76,0.84,0.95,1.09,1.27,1.52,and 1.90.The masses of baryons N,Σ,Ξ,andΛat different temperatures were also computed.The simulations were performed on an anisotropic lattice with N_(f)=2+1 flavours of clover fermion at a quark mass corresponding to mπ=384(4)MeV.The thermal ensembles were provided by the FASTSUM collaboration,whereas the zero temperature ensembles were provided by the Hadspec collaboration.We also calculated the spectral density of the correlation function of those particles.The spectral density distributions show a rich peak structure at the lowest temperature;at intermediate temperatures,the mass values of those particles obtained by the extrapolation method reflect a two-peak structure.While the spectral density for the octet baryon becomes smooth at T/T_(c)=1.27,1.52,and 1.90,the spectral density for the H-dibaryon becomes smooth at T/T_(c)=1.90.At T/T_(c)=0.24,the mass difference of the H-dibaryon andΛpair,expressed asΔm=m_(H)−2m_(Λ),was estimated to beΔm=−14.6(6.2)MeV,which suggests the existence of a bound H-dibaryon state.